The invention relates to a vacuum valve including a valve housing which comprises a valve seat, a closure member which, in a closed position, is pressed against the valve seat with the vacuum valve in a closed state and in an open position is raised from the valve seat with the vacuum valve in an open state, and a manual actuating means, by means of which the closure member is displaceable in a linear manner in a closing direction from the open position into the closed position and in a direction opposite the closing direction from the closed position into the open position and which comprises a screw transmission, which is actuatable by means of a rotational element and has a first driving part which is connected to the rotational element and a second driving part which is connected to the closure member, wherein the first and second driving parts, one of which comprises an external thread and the other an internal thread, are in threaded engagement and as a result of rotating the rotational element in a closing direction of rotation the closure member, which is situated in the open position, is displaceable in the closing direction and as a result of rotating the rotational element in an opening direction of rotation, which is opposite to the closing direction of rotation, the closure member, which is situated in the closed position, is displaceable in a direction opposite the closing direction and wherein there is present a closing spring, which acts upon the closure member in the closing direction with the closure member in the closed position.
Vacuum valves where the closure member is adjusted in a linear manner between the open position and the closed position by means of a manual actuating means have become known in particular in the form of angle valves. In the case of angle valves, the axes of the valve openings of the valve housing, which communicate with one another when the vacuum valve is open and are sealed in relation to one another when the vacuum valve is closed, are at an angle to one another, in particular a right angle. The valve seat, in this connection, is generally coaxial with respect to one of the valve openings. In another embodiment of such previously known vacuum valves, the first and second valve openings are coaxial to one another and the valve seat is in a plane that is inclined hereto, the linear adjustment of the closure member being effected in a direction which is at an angle to the axes of the valve openings.
Angle valves with manual actuating means proceed, for example, from DE 31 25 034 A1 and DE 10 2008 003 725 A1. A threaded spindle, which is in threaded engagement with a portion of the valve housing which comprises an internal thread and consequently forms a (fixed) spindle nut, is connected to the manually actuatable rotational element, which is realized in the form of a rotational knob or hand wheel. The closure member is connected to the threaded spindle by means of a rod.
In the case of a further previously known, commercially obtainable angle valve with manual actuating means, the threaded spindle which is connected to the rotational element comprises first and second threaded portions. The first threaded portion is screwed into an internal thread of the closure member. The second threaded portion is screwed into an internal thread of a valve rod which is connected to the closure member. The closure member and the valve rod, in this connection, are non-rotatably secured by means of a bellows which extends between the closure member and the valve housing. The two threaded portions comprise threads with different directions of rotation, that is a right-handed and a left-handed thread. Rotating the rotational element results in generating a travel on the one hand between the threaded spindle and the valve housing and on the other hand a travel in the same direction between the threaded spindle and the valve rod. The number of necessary revolutions of the rotational element for opening and closing the vacuum valve is halved as a result.
A vacuum valve of the type mentioned in the introduction proceeds from US 2006/0169940A1. An exemplary embodiment which is realized in the form of an angle valve is shown where the threaded spindle is mounted in the valve housing so as to be rotatable but axially non-displaceable. A non-rotatably secured threaded nut is arranged on the threaded spindle and a spring is arranged between the threaded nut and the closure member. The spindle nut consequently influences the closure member by means of the spring. Once the closure member has been placed on the valve seat, the desired pressing force can consequently be achieved by compressing the spring in a corresponding manner. This valve is in particular a high vacuum valve, the closure member consisting completely of metal at least in portions which adjoin the valve seat.
Apart from manually actuated angle valves, angle valves which are driven by means of pneumatically acting piston/cylinder units are frequently used. These types of vacuum valves proceed, for example, from US 2009/0194728A1, DE 40 23 845 C1 and U.S. Pat. No. 6,289,932B1. In order to ensure that the vacuum valve is closed in the event of the pressure medium failing, closing springs which act between the valve housing and the closure member are used.
Other types of vacuum valves with linearly adjustable closure members proceed, for example, from U.S. Pat. No. 7,011,294, DE 37 17 724 A1 and DE 38 31 249 A1. In the case of the vacuum valve made known from U.S. Pat. No. 7,011,294, the closure member is realized in a wedge-shaped manner. DE 37 17 724 A1 and DE 38 31 249 A1 show vacuum valves with seals and sealing faces, which interact with said seals and comprise other three-dimensional forms.
A vacuum valve which is realized in the form of an angle valve and has manual actuating means proceeds from U.S. Pat. No. 6,669,170B2. The rotational element is provided with a curved surface which interacts with a curved surface which is arranged on the valve housing. The interacting curved surfaces provide a type of link guide system such that the rotational element is displaced axially when rotated. The valve rod which is mounted on the closure member is provided with a flange. A closing spring acts between the valve housing and the closure member. With the closure member in the open position, said closing spring pulls the flange mounted on the valve rod against a stop face of the rotational element. Latching-in elements act between the flange and the rotational element such that the rotational element is able to be latched in different rotational positions. With the closure member in the closed position, the flange is able to be raised from the stop face. The realization of the manual actuating means of said vacuum valve is connected to increased production expenditure, in particular due to the realizations of the interacting curved surfaces and of further interacting parts of said manual actuating means.